Server advice.

Hi guys,
We’re thinking of buying a new server for our hosting needs. Think we host it ourselves here in Spain, so the advice has to be “worldwide” and not located in US, UK or any other country.
Here is what we need: a machine to run with Interworx with dual processors, a small disk (not more than 80GB is needed and could be SATA) and it must run without a twich for around 3 years. The budget is between $1500 - $2000 (1200? - 1800?). We really like Dells and would prefer rack over tower, but we do have plenty of space to have it.
No need for drac card or any fancy stuff.
Could you please advice us on machines that you’ve used / are using and the results from them?
Could you advice on processor (we really like Intel, but we haven’t tried any AMDs), disk models (difference in performance between SATA,SAS and SCSI)? and RAID cards (must have raid 1 or superior). We will be going for around 4GB of RAM (shouldn’t be needing more) to host around 150 sites.
Thanks a lot!